This invention relates to the production of shelf-stable composite food products, particularly composite snack food products, having a unique texture which is both crispy and chewy, yet does not give the impression of textural dichotomy.
Texture is a major factor in determining consumer acceptance in the food industry, particularly where snack foods are concerned. Consequently, the snack food industry continually strives to develop products having unique texture characteristics or unusual combinations of texture and flavor characteristics which are pleasing to the consumer. Studies of consumer preferences have repeatedly shown a marked preference for products which combine different textures, for example, products which are both chewy and crunchy. Some products achieve this combination of textures by incorporating discrete regions of food products having different textures. This type of product is exemplified by so-called "granola bars", which have a chewy binder material containing a plurality of food pieces of differing texture, such as nuts, cereals, seeds, dried fruits, etc., distributed throughout the binder. Products having discrete, distinguishable regions of differing textures are characterized herein as having textural dichotomy or textural variety.
Products of the prior art having textural dichotomy or textural variety, resulting from the incorporation of food components of differing texture, have suffered from a problem of shelf stability. This problem has been caused by the migration of water from discrete food components of higher water content to food components of lower water content within the product. The migration of water causes individual food components to lose their texture and flavor identities over time. In products such as granola bars, the water activity of the binder matrix determines the rate at which moisture migrates from one component to another. Water activity, which is the ratio of the fugacity of water within the substance being studied (i.e., the binder) to the fugacity of pure water, can be considered to be a measure of the tendency of the substance to allow water migration.